In thermoelectric materials a temperature gradient results in the generation of an electric field – a phenomenon known as the Seebeck effect – making them applicable for powering wearable electronics or for converting waste heat into electrical energy. Generally, a prerequisite for a large Seebeck coefficient is a strong asymmetry for the electronic density of states around the Fermi level. As such, semiconductors have garnered considerably more interest than metals, due to their intrinsic band gaps. Here we investigate the thermoelectric effect in bimetallic NixAu1-x alloys, where the nickel atoms are added as impurities to gold. The strong Seebeck effect here can be attributed to energy-dependent scattering of conducting Au-s electrons into localized Ni-d states around the Fermi level. The scattering rates due to both Ni impurities and the electron-phonon interaction are estimated as being proportional to the density of states of the Ni-d states, as per Fermi's golden rule. Thus, by using Mott's formula in conjunction with the Nordheim-Gorter relation for the calculation of the total Seebeck coefficient due to multiple independent scattering mechanisms, we completely circumvent the issue of calculating any resistivities. The resulting implementation can be seen to be equivalent to the DOS-1 approximation. Using a tight-binding DFT implementation, the Seebeck coefficient and figure of merit are calculated for a range of Ni concentrations and temperatures, with the maximum effect obtained at an Ni concentration of ~ 44 % and temperature T = 1200 K; yielding S = -113 µV/K and zTmax = 0.68. Our calculations are in excellent agreement with recent experiments at high temperature. As such, our work adds to the notion of NiAu alloys having high potential as thermoelectric materials, while simultaneously lending credibility and explanatory power to the DOS-1 approximation.